ABSTRACT Glioblastomas rank among the most lethal of cancers with decades of research adding only a few months to the median survival of patients afflicted with these tumors. The limitations in current therapy have many causes, but one contributing force is the presence of complex cellular heterogeneity that phenocopies the normal brain hierarchy. Normal tissue specific stem cells within this hierarchy pose a danger due to their ability to undergo sustained proliferation. In healthy tissues, stem cells reside in specific niches that provide maintenance cues that constrain proliferation, and these same cells differentiate upon exiting the niche. The stem cell microenvironment is associated with regional variation in oxygen, pH, and nutrient availability. Thus, it is almost certain that the metabolic reprogramming that occurs within the context of oncogenesis represents an element of the cancer stem cell niche. As mitochondrial morphology is linked to metabolic capacity and lineage specification, we are investigating the role of mitochondrial dynamics in driving bioenergetic changes that promote cancer stem cell growth and proliferation. In preliminary studies, glioma stem cells were found to exhibit molecular regulation of mitochondrial fission that was distinct from non- stem tumor cells and neuroprogenitors. As targeting mitochondrial dynamics has been linked to neural protection in degenerative disease, we propose that targeting this heterogeneity in mitochondrial dynamics may represent a selective point of vulnerability for glioma stem cells. In the proposed studies, we will investigate the role of mitochondrial fission in sustaining cancer stem cell health and as a therapeutic modality. Collectively, successful completion of the proposed experiments will provide an enhanced model of glioma hierarchy and drive the development of novel clinical therapies.